Methods and apparatus for crossing occlusions in blood vessels

Abstract

Exemplary embodiments of the present disclosure are directed to a device for facilitating treatment via a vascular wall defining a vascular lumen containing an occlusion therein. The device includes an intravascular device including a shaft having a distal end and a proximal end. The device further includes a handle assembly fixed about the proximal end of the shaft, the handle assembly including a first portion. Further rotation of the first portion in a first direction about a longitudinal axis of the shaft causes rotation of the shaft in the first direction when a torque applied by the first portion to the shaft is below a first maximum torque. Still further, rotation of the first portion in the first direction about a longitudinal axis of the shaft does not cause rotation of the shaft in the first direction when the torque applied by the first portion to the shaft is equal to or above the first maximum torque.

1. A device for facilitating treatment of a blood vessel, the device comprising:
 a shaft having a distal end and a proximal end; 
 a handle assembly fixed about the proximal end of the shaft, the handle assembly including a first portion, wherein rotation of the first portion in a first direction about a longitudinal axis of the shaft causes rotation of the shaft in the first direction when a torque applied by the first portion to the shaft is below a first maximum torque; 
 a first camming element having a protrusion that includes a first ramped surface and a second surface; and 
 a second camming element having a wall, 
 wherein rotation of the first portion in the first direction about the longitudinal axis of the shaft does not cause rotation of the shaft in the first direction when the torque applied by the first portion to the shaft is above the first maximum torque, wherein the first ramped surface is configured to allow the wall of the second camming element to pass over a top of the protrusion when the first camming element is rotated with respect to the second camming element in the first direction, and the second surface is configured to prevent the wall of the second camming element from passing over a top of the protrusion when the first camming element is rotated with respect to the second camming element in a second direction, 
 wherein the shaft is an elongate shaft comprising one or more flexible elements, the shaft being configured to traverse along a blood vessel. 
 
     
     
       2. The device of  claim 1 , wherein the handle assembly provides an audible indication when the torque applied by the first portion to the shaft is above the first maximum torque. 
     
     
       3. The device of  claim 2 , wherein the audible indication comprises a clicking sound. 
     
     
       4. The device of  claim 1 , wherein the handle assembly provides a tactile indication when the torque applied by the first portion to the shaft is above the first maximum torque. 
     
     
       5. The device of  claim 4 , wherein the tactile indication comprises vibration of the first portion of the handle assembly. 
     
     
       6. The device of  claim 1 , wherein rotation of the first portion in a second direction about the longitudinal axis of the shaft causes rotation of the shaft in the second direction when a torque applied by the first portion to the shaft is below a second maximum torque. 
     
     
       7. The device of  claim 6 , wherein rotation of the first portion in the second direction about the longitudinal axis of the shaft does not cause rotation of the shaft in the second direction when the torque applied by the first portion to the shaft is above the second maximum torque. 
     
     
       8. The device of  claim 6 , wherein the second maximum torque is greater than the first maximum torque. 
     
     
       9. The device of  claim 6 , wherein the handle assembly provides an audible indication when the torque applied by the first portion to the shaft is above the second maximum torque. 
     
     
       10. The device of  claim 9 , wherein the audible indication comprises a clicking sound. 
     
     
       11. The device of  claim 6 , wherein the handle assembly provides a tactile indication when the torque applied by the first portion to the shaft is above the second maximum torque. 
     
     
       12. The device of  claim 11 , wherein the tactile indication comprises vibration of the first portion of the handle assembly. 
     
     
       13. The device of  claim 1 , further including a torque limiting mechanism, the torque limiting mechanism including a set of camming elements. 
     
     
       14. The method of  claim 13 , wherein the set of camming elements includes the first camming element, the second camming element disposed between the first camming element and a third camming element, wherein the third camming element is fixed to the first portion. 
     
     
       15. The device of  claim 14 , wherein the second camming element is rotatable about the longitudinal axis relative to the first camming element and the third camming element. 
     
     
       16. The device on  claim 14 , wherein the second camming element defines at least one recess configured to receive the protrusion of the first camming element. 
     
     
       17. The device of  claim 14 , wherein the handle assembly further includes:
 a second portion including a handle axle; and 
 a cap threadedly engaged to the handle axle. 
 
     
     
       18. The device of  claim 17 , wherein a portion of the handle axle is disposed within the first camming element. 
     
     
       19. The device of  claim 17 , wherein the second portion of the handle assembly further includes a collet configured to secure the shaft to the second portion of the handle assembly. 
     
     
       20. The device of  claim 17 , wherein the first camming element defines an opening configured to receive a portion of the handle axle. 
     
     
       21. The device of  claim 20 , wherein the handle axle includes a plurality of splines, and wherein a portion of the plurality of splines is disposed within the first camming element. 
     
     
       22. The device of  claim 14 , wherein the first portion of the handle assembly includes a handle housing threadedly engaged to the third camming element. 
     
     
       23. The device of  claim 22 , wherein the third camming element is a cap. 
     
     
       24. The device of  claim 14 , wherein the second camming element defines at least one ramped surface. 
     
     
       25. The device on  claim 24 , wherein the third camming element defines at least one recess configured to receive the at least one ramped surface of the second camming element. 
     
     
       26. The device of  claim 1 , wherein the second surface of the protrusion of the first camming element is substantially parallel to the longitudinal axis. 
     
     
       27. The device of  claim 1 , wherein the second camming element is located distally of the first camming element. 
     
     
       28. The device of  claim 1 , wherein the first ramped surface is configured to allow the wall of the second camming element to pass over the top of the protrusion only when the torque applied by the first portion to the shaft is above the first maximum torque. 
     
     
       29. A medical device including:
 a shaft; and 
 a handle assembly, the handle assembly including:
 a first portion, wherein rotation of the first portion in a first direction about a longitudinal axis of the shaft causes rotation of the shaft in the first direction when a torque applied by the first portion to the shaft is below a first maximum torque; 
 a torque limiting mechanism in communication with the first portion, the torque limiting mechanism including:
 a first camming element having a protrusion that includes a first ramped surface and a second surface; and 
 a second camming element having a wall, 
 
 
 wherein rotation of the first portion in the first direction about the longitudinal axis of the shaft does not cause rotation of the shaft in the first direction when the torque applied by the first portion to the shaft is equal to or above the first maximum torque, wherein the first ramped surface is configured to allow the wall of the second camming element to pass over a top of the protrusion when the first camming element is rotated with respect to the second camming element in the first direction, and the second surface is configured to prevent the wall of the second camming element from passing over a top of the protrusion when the first camming element is rotated with respect to the second camming element in a second direction, 
 wherein the shaft is an elongate shaft comprising one or more flexible elements, the shaft being configured to traverse along a blood vessel. 
 
     
     
       30. The device of  claim 29 , wherein rotation of the first portion in a second direction about the longitudinal axis of the shaft causes rotation of the shaft in the second direction when a torque applied by the first portion to the shaft is below a second maximum torque. 
     
     
       31. The device of  claim 30 , wherein rotation of the first portion in the second direction about the longitudinal axis of the shaft does not cause rotation of the shaft in the second direction when the torque applied by the first portion to the shaft is above the second maximum torque. 
     
     
       32. The device of  claim 30 , wherein the second maximum torque is different than the first maximum torque. 
     
     
       33. The device of  claim 32 , wherein the first portion of the handle assembly includes a handle housing threadedly engaged to the third camming element. 
     
     
       34. The device of  claim 29 , wherein the torque limiting mechanism further includes a third camming element. 
     
     
       35. The device of  claim 34 , wherein the second camming element is disposed between the first camming element and the third camming element, and the third camming element is fixed to the first portion. 
     
     
       36. The device of  claim 35 , wherein the second camming element is rotatable about the longitudinal axis relative to the first camming element and the third camming element. 
     
     
       37. The device of  claim 35 , wherein the handle assembly further includes:
 a second portion including a handle axle; and 
 a cap threadedly engaged to the handle axle. 
 
     
     
       38. The device of  claim 29 , wherein the second surface of the protrusion of the first camming element is substantially parallel to the longitudinal axis. 
     
     
       39. The device of  claim 29 , wherein the second camming element is located distally of the first camming element. 
     
     
       40. The device of  claim 29 , wherein the first ramped surface is configured to allow the wall of the second camming element to pass over the top of the protrusion only when the torque applied by the first portion to the shaft is above the first maximum torque. 
     
     
       41. A device for facilitating treatment of a blood vessel, the device comprising:
 a shaft having a distal end and a proximal end; 
 a handle assembly disposed about the shaft; 
 a first camming element having a protrusion that includes a first ramped surface and a second surface; and 
 a second camming element having a wall, 
 the handle assembly comprising a first portion and a torque limiting mechanism coupling the first portion to the shaft; 
 wherein the torque limiting mechanism allows relative movement between the first portion and the shaft when the first portion is being rotated in a first direction and a torque applied to the shaft has exceeded a first maximum torque, wherein the first ramped surface is configured to allow the wall of the second camming element to pass over a top of the protrusion when the first camming element is rotated with respect to the second camming element in the first direction, and the second surface is configured to prevent the wall of the second camming element from passing over a top of the protrusion when the first camming element is rotated with respect to the second camming element in a second direction, 
 wherein the shaft is an elongate shaft comprising one or more flexible elements, the shaft being configured to traverse along a blood vessel. 
 
     
     
       42. The device of  claim 41 , wherein the torque limiting mechanism allows relative movement between the first portion and the shaft when the first portion is being rotated in a second direction and the torque applied to the shaft has exceeded a second maximum torque. 
     
     
       43. The device of  claim 42 , wherein the second maximum torque is different than the first maximum torque. 
     
     
       44. The device of  claim 42 , wherein:
 the shaft comprises a left hand wound coil; 
 the first direction is a clockwise direction; and 
 the first maximum torque is greater than the second maximum torque. 
 
     
     
       45. The device of  claim 42 , wherein:
 the shaft comprises a right hand wound coil; 
 the second direction is a counterclockwise direction; and 
 the second maximum torque is greater than the first maximum torque. 
 
     
     
       46. The device of  claim 41 , wherein the shaft comprises a coil. 
     
     
       47. The device of  claim 46 , further comprising a distal tip fixed to a distal end of the coil and a proximal hub fixed to a proximal end of the coil. 
     
     
       48. The device of  claim 41 , wherein the torque limiting mechanism transfers torque between the first portion and the shaft when the first portion is being rotated in a first direction and the torque applied to the shaft is less than or equal to the first maximum torque. 
     
     
       49. The device of  claim 41 , wherein the torque limiting mechanism includes the first camming element. 
     
     
       50. The device of  claim 49 , wherein the first camming element is coupled to the shaft so that the first camming element is not free to rotate relative to the shaft. 
     
     
       51. The device of  claim 49 , wherein the torque limiting mechanism includes the second camming element. 
     
     
       52. The device of  claim 51 , wherein the second camming element includes:
 a protrusion including a first ramped surface and a second surface; and 
 a first ramp engaging surface. 
 
     
     
       53. The device of  claim 52 , wherein the torque limiting mechanism comprises a cap fixed to the first portion, the cap having a wall configured to interact with the second surface of the second camming element and a second ramp engaging surface configured to interact with the first ramped surface of the second camming element. 
     
     
       54. The device of  claim 53 , wherein:
 the first ramp engaging surface of the second camming element engages the first ramped surface of the first camming element when the first portion is rotated in the first direction; and 
 the second ramp engaging surface of the cap engages the first ramped surface of the second camming element when the first portion is rotated in a second direction. 
 
     
     
       55. The device of  claim 53 , wherein:
 the protrusion of the first camming element has a first shape; 
 the protrusion of the second camming element has a second shape; and 
 the second shape is different than the first shape. 
 
     
     
       56. The device of  claim 53 , wherein:
 the first ramped surface of the first camming element has a first pitch; 
 the first ramped surface of the second camming element has a second pitch; and 
 the second pitch is different from the first pitch. 
 
     
     
       57. The device of  claim 53 , wherein:
 the protrusion of the first camming element has a first maximum height; 
 the protrusion of the second camming element has a second maximum height; and 
 the second maximum height is different than the first maximum height. 
 
     
     
       58. The device of  claim 53 , wherein the first ramp engaging surface travels over and beyond the first ramped surface of the first camming element when the first portion is being rotated in the first direction and the torque applied to the shaft has exceeded the first maximum torque, and wherein the second ramp engaging surface travels over and beyond the first ramped surface of the second camming element when the first portion is being rotated in a second direction and a torque applied to the shaft has exceeded a second maximum torque. 
     
     
       59. The device of  claim 41 , wherein the second surface of the protrusion of the first camming element is substantially parallel to a longitudinal axis of the device. 
     
     
       60. The device of  claim 41 , wherein the second camming element is located distally of the first camming element. 
     
     
       61. The device of  claim 41 , wherein the first ramped surface is configured to allow the wall of the second camming element to pass over the top of the protrusion only when the torque applied by the first portion to the shaft is above the first maximum torque.